Magma power for geothermal energy?

The geothermal field at Krafla, Iceland, is yielding new insights on geothermal heat. (Peter Schiffman/UC Davis photo)

When a team of scientists drilling near an Icelandic volcano hit
magma in 2009, they had to abandon their planned experiments on geothermal
energy. But the mishap could point the way to an alternative source of
geothermal power.

"Because we drilled into magma, this borehole could now be a
really high-quality geothermal well," said Peter Schiffmann, professor of
geology at UC Davis and a member of the research team along with fellow UC
Davis geology professor Robert Zierenberg and UC Davis graduate student Naomi
Marks. The project was led by Wilfred Elders, a geology professor at UC
Riverside.

A paper describing geological results from the well was published
in Geology.

When tested, the magma well produced dry steam at 750 degrees
Fahrenheit (400 degrees Celsius). The team estimated that this steam could
generate up to 25 megawatts of electricity—enough to power 25,000 to 30,000
homes.

That compares to 5 to 8 megawatts produced by a typical geothermal
well, Elders said. Iceland
already gets about one-third of its electricity and almost all of its home
heating from geothermal sources.

The team was drilling into the Krafla caldera as part of the
Iceland Deep Drilling Project, an industry-government consortium, to test whether
"supercritical" water—very hot water under very high pressure—could
be exploited as a source of power.

They planned to drill to 15,000 ft—more than two miles deep—but at
6,900 ft, magma (molten rock from the Earth's core) flowed into the well,
forcing them to stop.

The composition of magma from the borehole is also providing
insight into how magmas form beneath Iceland, Schiffmann said.

The team included researchers from two Icelandic power companies,
HS Orka hf and Landsvirkjun Power; Iceland GeoSurvey; the U.S. Geological
Survey; Stanford Univ.; New Mexico Institute of Mining and Technology; and the Univ.
of Oregon, Eugene; as well as UC Davis and UC Riverside.

The work was funded by the National Science Foundation and the
International Continental Scientific Drilling Program.